The demonstration of protein expression and biological efficacy of gene delivery systems is critical to the successful development of gene transfer vectors and therapies. A cell physiology and tissue culture core has been in operation at Johns Hopkins University since 1989 funded by the Cystic Fibrosis Foundation through the Research Development Program. This core has considerable expertise in the following areas: assaying for normal and defective function of CFTR by general assays such as: 1. 36Cl- efflux and SPQ and more specific assays such as patch clamping; 2. generating polyclonal anti-CFTR antibodies in both rabbit and chicken; 3. assaying for protein expression by Western blotting; and 4. determining the distribution of CFTR in heterologous cells and in animal (rabbit, rat and primate) cells. Work from this core was instrumental in the identification of adenoviral (12) and adeno-associated virus (2,3-6) systems as potential therapeutic agents which has caused much excitement lately and resulted in five protocols approved by the RAC (Recombinant DNA committee). The recent development of gene transfer technologies as potential therapies has increased the need of our Expression Core. The current Cell Physiology and Tissue Culture Core will be expanded to meet the needs of this new Gene Therapy Center. The Expression Core will be both a research and development core as well as providing support for the projects within this Gene Therapy Center.